Nicolò Bagno

Making Silicon Crystals Step 1. Melt a lot of silicon down into a hot pool of liquid silicon. Step 2. Adjust the temperature until the pool is just above its melting point. Step 3. Dip a cold thing into the pool (seed)and the silicon will start to freeze onto it. Step 4. Slowly rotate the seed to keep everything round. Step 5. Very slowly lift this thing out of the pool. Step 6. Lift it out at juuuussssst the right speed so that the silicon keeps it wetted at the bottom and freezes to it as it is retracted. The pull speed controls how big the diameter is. Step 7. When it start to get a bit long just lift it faster and it will taper off. This is why silicon ingots have their distinctive shape. Once you know the process the shape is very intuitive. These ingots are then salami sliced into wafers and those wafers then get etched into chips. This is called the Czochralski (CZ) method, if you can create a hot pool of something you can generally produce giant single crystals of that material. It works for semiconductors, optical crystals, metals, anything where you want a bulk crystal with controlled grain. Turbine blades use a different method because they have to be made with cooling channels and other intricate features that cannot be produced with reductive machining.

Weapons of Mass Production Today there are a handful of single assets that gate huge sectors of the economy. The criteria should be something like >50% of the global supply passes through this one cool thing. • Falcon 9 Commercial access to space is 90% via the Falcon 9 launch system. • Ulsan shipyard Large high quality FPSOs and LNG tankers are almost exclusively manufactured here. • Muroran forge press Giant forged ingots >200 tons are mostly made in Japan and by this giant forge press. • Zeiss vacuum grinder The mirrors that allow ASML to do frontier EUV lithography are made by 1 machine. There are a few others but you get the idea, what else should be on the list?

High NA-EUV Lithography Zeiss is beginning production of their High NA-EUV systems for ASML. “High NA” means high numerical aperture, which is a measure of the angular range from which an optical system can pick up light. For context High NA has numerical aperture of 0.55, whereas current EUV NA is 0.33 A 66% improvement. That’s a feature density improvement of 1.67^2=2.789 so a near tripling of transistor density per unit area. It brings the critical dimension down to 8nm from 13nm. Q: How did Zeiss achieve this? A: With great difficulty. • The projection optics system is 40,000 parts and around 12 tonnes. • The illumination system is 25,000 parts and is 6 tonnes. • The machine that manufacturers these mirrors is based in Germany, and consists of 100,000 parts and is 150 tonnes, the machining chamber itself is a 5m x 5m x 10m vacuum chamber. The mirrors are machined for 3 months[!] to achieve a precision equivalent to 1mm deviation over an area the size of the Pacific Ocean. It’s worth noting here that theoretical maximum NA = 1.0 Hyper NA (>0.7 and achieved using 8 mirrors) is expected the enter production 2032 - 2035. That brings the critical dimension down to around 6nm and that might be the end, a single silicon atom is 0.23nm so the precision would be +/- 24 atoms. Fun note… there is a category of lathes and machine tools called “ultra-precision” and these have axis resolutions of 1-2nm and can produce contoured shapes to 25nm accuracy. You can buy “ultra-precision” machines, grinding machines for optical equipment have incredibly precise axis control because surface asperity on a mirror is visible to the eye. B23B is the IPC/CPC class, and it teaches some interesting niche stuff (tells you where the future is going, even with trade secrets omitted).